There's not only one way to do anything else, and as such nobody was excluded from gameplay in Horizons.
If we're talking a pure non-combat approach then the following engineers require at least some combat participation either for themselves or because an engineer earlier in the chain does:
Bubble: Ishmaak, Dekker, Sarge, Jameson, McQuinn, Jean, Turner, Vatermann, Tarquin
Colonia: Brandon, Olmanova
Before the Colonia engineers were added
and fully upgraded that meant a purely non-combat player had no way to obtain (bold for ones they
still can't obtain):
-
armour above G1
- any life support mod at all (Dorn has G5)
- power plant G5 (Dorn has G5)
-
any AFMU mods
-
interdictor above G3
-
HRPs above G1
- any refinery mods (Hicks has G5)
-
SCBs above G1
-
shield boosters above G3
- (also a bunch of weapon blueprints, let's assume they don't need them)
If we
also exclude activities with a risk of needing to run away from combat (anything which involves carrying cargo, then!) - if you're happy to just accept that you take a (no cost) rebuy and lose that set of materials when the scavengers show up to a crash site, or use the shield on your G3 suit to tank them long enough to get back in your SRV/ship and run away (the surface equivalent of evading an interdiction), you can efficiently get a lot more Odyssey materials too - so really to be fair we should exclude all cargo-carrying activities as having the
risk of combat, and that also means you can't unlock the following engineers:
Bubble: all of them except maybe the Dweller [1]
Colonia: all of them
...which limits you to the G5 power distributor and a few lower-grade laser upgrades you don't need.
Plus as you've already mentioned Thargoid and Guardian materials require combat (or at least being shot at) to obtain, and are required for a substantial number of tech broker unlocks including ones with non-combat uses. Under the "no carrying cargo" non-combat rule you're also not allowed to unlock most of the human tech broker options as they'll require taking cargo from a station which produces it to a different station with the tech broker.
A purely no-risk-of-combat approach was never viable in Horizons if you wanted engineered or otherwise upgraded modules. That may not matter to you personally - if you can reliably dodge interdictions, and don't count "massive overkill versus skimmers" as combat, then you can get enough of the Horizons engineers not to matter much that you're missing the rest - but then equally Odyssey is fully possible "without combat" for someone with a marginally different definition of "non-combat" to you.
[1] You'd have to get a mission cargo reward from a courier mission, use Apex to complete the courier mission without risk of combat, then have the courier mission be to a destination where that cargo is illegal and you can sell it to the black market immediately, or to a destination where the cargo will be illegal after a BGS conflict concludes, and wait in the docking bay for that to happen. And you have to do that five times to different stations. But still, technically possible so I guess this hypothetical player can have their Power Distributors...
